Door knocker



FIG. 1 is a front perspective view from below of the door knocker showing my new design;

FIG. 2 is an inverted front view thereof;

FIG. 3 is a bottom view thereof;

FIG. 4 is an inverted top view thereof;

FIG. 5 is a rear view thereof;

FIG. 6 is a right side view thereof; and,

FIG. 7 is a left side view thereof. 

The ornamental design for a door knocker, as shown. 